Syntheses of Cyclic Hydroxamic Acids and Lactams with 2,3-dioxo-1,4-benzoxazine skeleton
摘要:
Ethyl 2-nitrophenyl oxalate (1 a) and its 5-methoxy derivative (1 b) were subjected to catalytic hydrogenations over 3 % Pt (S) on carbon in different solvents. Thus, hydrogenation in acetic acid yielded 4-hydroxy-2,3-dioxo-1,4-benzoxazine (2a) and its 7-methoxy derivative (2 b) by reductive cyclization, the dehydro forms of the naturally occurring cyclic hydroxamic acids DIBOA and DIMBOA from Gramineae. In contrast, hydrogenation of esters 1 in methanol results in the formation of amides 3 by acyl group migration. On heating, amides 3 undergo lactonization to form lactone-lactames 4, which in turn undergo ring opening to give amides 3 when refluxed in ethanol.
[1,4]Benzoxazine-2,3-diones as antiallergic agents
作者:Bernard Loev、Howard Jones、Richard E. Brown、Fu Chih Huang、Atul Khandwala、Mitchell J. Leibowitz、Paula Sonnino-Goldman
DOI:10.1021/jm00379a006
日期:1985.1
The synthesis of a series of [1,4]benzoxazine-2,3-diones and a new class of compounds, benzobisoxazinetetrones, is described. These compounds were evaluated for their effect in the rat mast cell (RMC) test passively sensitized in vitro with rat antiovalbumin serum and for their effect in inhibitory passive cutaneous anaphylaxis (PCA) in the rat. Some of these compounds are of the same potency level as disodium cromglycate in the RMC test and some are effective orally in PCA.
LOEV, B.;JONES, H.;BROWN, R. E.;HUANG, FU-CHIH;KHANDWALA, A.;LEIBOWITZ, M+, J. MED. CHEM., 1985, 28, N 1, 24-27
作者:LOEV, B.、JONES, H.、BROWN, R. E.、HUANG, FU-CHIH、KHANDWALA, A.、LEIBOWITZ, M+